Method and system for wholesomeness inspection of freshly slaughtered chickens on a processing line

ABSTRACT

An imaging system containing an electron-multiplying charge-coupled device detector and line-scan spectrograph is used for identifying wholesome and unwholesome freshly slaughtered chicken carcasses on high-speed commercial chicken processing lines. Multispectral imaging algorithms allow for real-time online identification of wholesome and unwholesome chicken carcasses.

BACKGROUND OF THE INVENTION

The present invention relates to an online line-scan imaging systemcapable of both hyperspectral and multispectral visible/near-infraredreflectance and to a method of using the system to inspect freshlyslaughtered chickens on a processing line for wholesomeness andunwholesomeness. The system includes imaging apparatus, methods forimage analysis and processing, and methods for use of this system foronline inspection.

The Federal Meat Inspection Act of 1906 mandated postmortem inspectionof meat and poultry carcasses and authorized the U.S. Department ofAgriculture (USDA) to inspect slaughter and processing operations andsanitation for meat and poultry products intended for human consumption.The 1957 Poultry Product Inspection Act mandated postmortem inspectionof every bird carcass processed by a commercial facility. Since then,USDA inspectors have conducted on-site organoleptic inspection of allchickens processed at U.S. poultry plants for indications of diseases ordefects. Inspectors of the USDA Food Safety and Inspection Service(FSIS) examine by sight and by touch the body, the inner body cavitysurfaces, and the internal organs of every chicken carcass duringprocessing operations.

With the 1996 final rule on Pathogen Reduction and Hazard Analysis andCritical Control Point (HACCP) systems (USDA, Final Rule, Fed. Reg.,Volume 61, 38805-38989, 1996), FSIS implemented the HACCP and PathogenReduction programs in meat and poultry processing plants throughout thecountry to prevent food safety hazards, to set specific food safetyperformance standards, and to establish testing programs to ensure thatthe performance standards are met, through the use of science-basedprocess control systems. More recently, FSIS has also been testing theHACCP-Based Inspection Models Project (HIMP) in a small number ofvolunteer plants (USDA, Proposed Rule, Fed. Reg., 62: 31553-31562(1997). HIMP requirements include zero tolerance for unwholesomechickens exhibiting symptoms of “septox”—a condition of eithersepticemia or toxemia. Wholesome chickens do not exhibit symptoms of“septox”.

Septicemia is caused by the presence of pathogenic microorganisms ortheir toxins in the bloodstream, and toxemia results from toxinsproduced by cells at a localized infection or from the growth ofmicroorganisms. Septox birds are considered to be unwholesome and USDAinspectors remove these unwholesome birds from the processing linesduring their bird-by-bird inspections, which can, by law, be conductedat a maximum speed of 35 birds per minute (bpm) for an individualinspector. The inspection process is subject to human variability, andthe inspection speed restricts the maximum possible output for theprocessing plants while also making inspectors prone to fatigue andrepetitive injury problems. This limit on production throughput,combined with increases in chicken consumption and demand over the past2 decades, places additional pressure on both chicken production andsafety inspection system. U.S. poultry plants now process over 8.8billion broilers annually (USDA, Poultry Production and Value—2006Summary (2007). During processing at a typical U.S. poultry plant, birdsare first slaughtered on kill lines and then transferred to eviscerationlines on which inspection stations are located. Commercial eviscerationlines in the U.S. currently may be operated at speeds up to 140 bpm;however, such processing lines require up to four inspection stations,each with an FSIS inspector to conduct bird-by-bird inspection at thebpm speed limit.

Machine visiori technologies have been developed to address a variety offood and agricultural processing applications. Various sensingtechniques such as RGB (red/green/blue) color imaging, visible andnear-infrared (Vis/NIR) spectroscopy and imaging, fluorescencespectroscopy and imaging, and X-ray imaging, have been investigated forpotential use in food processing and online inspection applications(Daley et al., Proc. SPIE, 2345: 403-411 (1994); Delwiche et al., CerealChem., 75: 412-416 (1998); Chao et al., Applied Engineering inAgriculture, 19(4): 453-458 (2003); Chao et al., Applied Engineering inAgriculture, 20(5): 683-690 (2004); Lu and Ariana, Applied Engineeringin Agriculture, 18(5): 585-590 (2002); Lu, Trans. ASAE, 46(2): 523-530(2003); Kim et al., Applied Optics, 42(9): 3927-3934 (2,002); Mehl etal., Applied Engineering in Agriculture, 18(2): 219-226, 2002; Vargas etal., J. Food Science, 70(8): 471-476 (2003); Chen et al., AppliedOptics, 40(8): 1195-2000 (2001).

A variety of methods for imaging whole chicken carcasses and chickenviscera/organs have been investigated for use in food safety inspectionof poultry. RGB color imaging of chicken spleens, hearts, and livers wasfound capable of identifying poultry disease conditions includingleucosis, septicemia, airsacculitis, and ascites in the laboratory (Taoet al., Proc. SPIE, 3544: 138-145 (1998); Chao et al., AppliedEngineering in Agriculture, 15(4): 363-369 (1999), but these methodsrequired precise presentation of the visceral organs and thus wereunsuitable for conventional poultry processing lines. A two-camerasystem using two wavebands in the visible spectrum for whole-carcassimaging was able to separate 90% of wholesome and unwholesome chickensat processing line speeds up to 70 bpm, but was not feasible for higherspeed processing (Park and Chen, J. Food Processing Engineering, 23(5):329-351 (2000); Chao et al., J. Food Engineering, 51(3): 185-192 (2002).

Thus there remains a need to develop systems that can inspect chickensfor wholesomeness in commercial processing lines which operate at speedsof at least 140 bpm.

We have found that with appropriate methods of hyperspectral analysisand algorithms for online image processing, a machine vision systemutilizing an EMCCD (Electron-Multiplying Charge-Coupled-Device) camerafor multispectral inspection can satisfy both the food safetyperformance standards and the high-speed production requirements (e.g.,at least 140 bpm) of commercial chicken processing. A system of thistype can perform food safety inspection tasks accurately and with lessvariation in performance at high speeds (e.g., at least 140 bpm), andhelp poultry plants to improve production efficiency and satisfyincreasing consumer demand for poultry products.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention is to provide animaging system for acquisition and processing of hyperspectral andmultispectral reflectance images of freshly slaughtered chickencarcasses on processing lines for food safety inspection.

A further object of the present invention is to provide an apparatus andprocess by which individual chicken carcasses can be detected forhyperspectral and multispectral imaging.

Another object of the present invention is to provide apparatus andprocesses by which wholesome and unwholesome chicken carcasses can beidentified using hyperspectral and multispectral imaging.

A further object of the present invention is to provide apparatus andprocesses which can identify wholesome and unwholesome chicken carcassesat speeds compatible with the speeds at which chicken processing linesare operated.

A still further object of the present invention is to provide areal-time automated inspection system for whole chicken carcasses whichcan quickly and accurately identify wholesome and unwholesome chickencarcasses.

Another object of the present invention is to provide a method ofhyperspectral reflectance image analysis for determining parameters tobe utilized for multispectral reflectance imaging inspection of freshlyslaughtered chickens.

A further object of the present invention is to provide a method usingmultispectral reflectance imaging for inspecting freshly slaughteredchicken carcasses on a poultry processing line for wholesomeness.

Another object of the present invention is to provide a method forinspecting chicken carcasses for wholesomeness by integrating theimaging system of the present invention with commercial chickenprocessing lines.

A further object of the present invention is to provide an improvedinspection process for detecting and for removing or divertingunwholesome birds from chicken processing lines.

Further objects and advantages of the invention will become apparentfrom the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a schematic diagram of the arrangement of thehyperspectral/multispectral imaging system for operation on a poultryprocessing line.

FIG. 1 b is a schematic diagram of the components of thehyperspectral/multispectral imaging inspection system. FIG. 1 c is aphotograph of the hyperspectral/multispectral imaging inspection systemon a commercial chicken processing line.

FIG. 2 is a flowchart of the calibration process for thehyperspectral/multispectral imaging inspection system.

FIG. 3 is a flowchart of the hyperspectral analysis method fordetermination of the region of interest (ROI) and key wavebands requiredto conduct multispectral imaging inspection of chickens forwholesomeness.

FIG. 4 is a flowchart of the method for online multispectral line-scanimaging inspection of chickens for wholesomeness.

FIG. 5 is a graph of the reflectance spectra of a Spectralon diffusereflectance standard when illuminated by the white LED line lights andby a mercury and neon calibration pen lamp.

FIG. 6 is a graph of the second-order polynomial regression model usedfor spectral calibration of the imaging inspection system using abinning of 1 by 4.

FIG. 7 shows images at four spectral wavebands of chicken carcasses thatwere acquired during hyperspectral line-scan imaging on the chickenprocessing line.

FIG. 8 shows a contour image of two chicken carcasses marked withexample locations of the SP (Starting Point), EP (Ending Point), m, andn parameters (described below) used for locating the ROI.

FIG. 9 is a graph of the range, for each possible ROI, of differencevalues between average wholesome and average unwholesome chickenspectra, for optimizing the ROI to be used for inspection of chickens.

FIG. 10 is a graph of average wholesome and average unwholesome chickenspectra, highlighting the 580 nm key waveband that can be used forintensity-based differentiation of wholesome and unwholesome chickens.

FIG. 11 is a graph of the average wholesome and average unwholesomechicken spectra, highlighting possible key wavebands that can be usedfor two-waveband ratio differentiation of wholesome and unwholesomechickens.

FIG. 12 is a graph of the mean and standard deviation for intensityvalue at key waveband 580 nm, and a second graph of the mean andstandard deviation for ratio value using 580 nm and 620 nm, forwholesome and unwholesome chickens.

FIG. 13 is an image of nine chickens with the optimized ROI highlightedon each chicken.

FIG. 14 is a scatterplot graph of the distribution of chicken carcassesimaged during multispectral inspection, by the number of ROI pixels andthe number of ROI lines for each chicken.

FIG. 15 is a diagram of the structure of the fuzzy logic membershipfunctions which use the intensity-based input value and ratio-basedinput value to create pixel-based decision outputs for wholesomenessclassification.

FIG. 16 shows a masked image (top) of nine chickens that highlights theROI pixels to be analyzed for each chicken, and a second image (bottom)highlighting the ROI pixels for each chicken that were classified aswholesome.

FIG. 17 is a scatterplot graph showing the distribution of chickencarcasses imaged during inspection shift 1, by the number of ROI pixelsand the final decision output for each chicken.

FIG. 18 is a scatterplot graph showing the distribution of chickencarcasses imaged during inspection shift 2, by the number of ROI pixelsand the final decision output for each chicken.

DETAILED DESCRIPTION OF THE INVENTION

For useful application to the task of automated chicken carcassinspection, an imaging system must be capable of operating at highspeeds compatible with those at which poultry processing lines areoperated. Commercial processing lines in the U.S. currently may beoperated at speeds up to 140 bpm. The system must accurately detectindividual birds on the processing line, process the spectral imagedata, and produce a classification result. Typical processing plantconditions also necessitate that the imaging system provide adequateillumination of the chicken carcasses for effective imaging. An imagingsystem capable of inspecting chicken carcasses with high speed andaccuracy on a processing line will improve production efficiency ofchicken processing plants and improve food safety inspection programsfor chicken products.

The present invention concerns in part a line-scan imaging systemcapable of both hyperspectral and multispectral reflectance imaging foronline operation on chicken processing lines, and methods ofhyperspectral analysis, multispectral classification of wholesome andunwholesome chickens for food safety inspection, and implementation ofthe system for operation on chicken processing lines.

Imaging system 10 (FIG. 1 a) includes a means for obtaining spectralimages 12, a lighting system 2, a means of providing a darknon-reflective imaging background 3, and a data processing unit 7. Oneembodiment of the present invention includes ahyperspectral/multispectral imaging system 10 (FIG. 1 b).Hyperspectral/multispectral imaging system 10 includes at least a meansfor obtaining spectral images 12, such as, for example, anElectron-Multiplying Charge-Coupled-Device (EMCCD) imaging detector 1A;a lighting system 2; and a data processing unit 7. The means forcollecting spectral images 12 for purposes of this embodiment includesan Electron-Multiplying Charge-Coupled-Device (EMCCD) 1A, a lensassembly 1B, and a line-scan spectrograph 1C.

Device 1A can be an Electron-Multiplying Charge-Coupled-Device (EMCCD).Examples of EMCCD include, for example, PhotonMAX 512 b (RoperScientific, Inc., Trenton, N.J.) and iXon and Luca (Andor TechnologyLimited, CT). EMCCD-based cameras can accommodate low-light imagingenvironments and both hyperspectral and multispectral imaging of rapidlymoving targets. Their high quantum efficiencies, rapid frame-transfermechanisms, and pre-output signal amplification viaelectron-multiplication also allow significantly improvedsignal-to-readout-noise ratios. When utilized for line-scan imaging,software controls for an EMCCD camera eliminate the need for themechanical operation of a shutter and can operate the same camera foreither hyperspectral or multispectral imaging without necessitatinghardware adjustments. Consequently, wavelengths selected throughhyperspectral analysis (described below) can be easily implemented forhigh-speed multispectral imaging of moving targets without the need forcross-system calibration.

Line-scan spectrograph 1C such as Hyperspec-VNIR Series C (HeadwallPhotonics, Inc., Fitchburg, Mass.) or ImSpector V10 (Specim/SpectralImaging Ltd., Oulu, Finland), has a nominal spectral range of about 400nm to about 1000 nm and attaches to the EMCCD imaging detector 1A forgenerating line-scan images. Lens assembly 1B includes a C-mount lenssuch as, for example, a Xenoplan (Schneider, Haugppauge, N.Y.) or aNikkor (Nikon Inc., Melville, N.Y.) lens and attaches to line-scanspectrograph 1C.

Imaging Device 1A has approximately 512×512 pixels and isthermoelectrically cooled to approximately −70° C. (for example via athree-stage Peltier device). The imaging device is coupled with a 14-bitor 16-bit digitizer 17, such as ST-133 (Roper Scientific, Inc., Trenton,N.J.) or CCI-23 (Andor Technology Limited, CT) with a pixel-readout rateof approximately 10 MHz to 30 MHz. An imaging spectrograph 1C (ImSpectorV10, Specim/Spectral Imaging Ltd., Oulu, Finland), and a C-mount lens 1B(Rainbow CCTV S6x11, International Space Optics, S.A., Irvine, Calif.)are attached to the EMCCD Imaging Device 1A. The spectrograph apertureslit of approximately 50 microns limits the instantaneous field of view(IFOV) of the imaging system to a thin line. Light from the linear IFOVis dispersed by a prism-grating-prism line-scan spectrograph andprojected onto the EMCCD Imaging Device 1A. The spectrograph creates atwo-dimensional (spatial and spectral) image for each line-scan, withthe spatial dimension along the horizontal axis and the spectraldimension along the vertical axis of the EMCCD Imaging Device 1A.

The image signals provided by the means for obtaining spectral images 12are input to a computer 7 via a 14-bit or 16-bit digitizer 17, such asthe ST-133 (Roper Scientific, Inc., Trenton, N.J.). The digitizer 17performs rapid analog-to-digital conversion of the image data for eachhyperspectral or multispectral line-scan image. These data are thenprocessed by the computer 7 for image analysis and classification ofwholesome and unwholesome pixels in the line-scan images.

The hyperspectral/multispectral imaging system requires lighting system2. Lighting system 2 includes an illuminator 2A with at least 10000 lux(lumen/m²) intensity and excitation wavelengths between about 400 nm andabout 800 nm, such as for example, two pairs of high power,broad-spectrum white light-emitting-diode (LED) line lights (LL6212,Advanced Illumination, Inc., Rochester, Vt.) and a line-regulated directcurrent power supply 2B, such as for example a Sola/Hevi-Duty S6 10A 24VDC power supply (EGS Electrical Group, Rosemont, Ill.). The lightingsystem is controlled manually. The hyperspectral/multispectral imagingsystem requires a means of providing a dark, non-reflective imagingbackground 3 such as, for example, a black non-reflective matte-surfaceacrylic or fabric panel.

The theoretical development of algorithms 20 which are used for thispurpose is based on the difference between spectral reflectance ofwholesome chickens versus that of unwholesome chickens. The assumptionwas made that a mathematical combination of remotely sensed spectralbands could be used to identify wholesome chickens and unwholesomechickens. The results generated by such a combination of spectral bandscorresponds to the color of chicken tissue in a given image pixel asaffected by the wholesomeness or unwholesomeness of the bird. The endresult of such computer analysis is the generation of a qualitativeanalysis such as a “wholesome/unwholesome” determination for eachchicken that passes in front of the means for obtaining spectral images.The developed algorithms 20 are implemented using commercial software 18such as MATLAB (MathWorks, Natick, Mass.) and LabView (NationalInstruments Corp., Austin, Tex.).

Hyperspectral/multispectral imaging system 10 requires calibrationbefore line-scan images can be acquired. Re-calibration is generally notrequired unless the physical arrangement of the components of theimaging system is disturbed. The first step in the calibration processwas to cool the imaging system to its operating temperature of −70° C.(FIG. 2, Box 2.1). The next step was to set image binning, which isdetermined by the spectral distribution of useful wavelengths and thesize of spatial image features to be processed for the application (FIG.2, Box 2.2). The original image size, 512×512 pixels, was reduced by 1×4binning to result in line-scan images with a spatial resolution of 512pixels (512 divided by 1) and a spectral resolution of 128 pixels (512divided by 4) in the spectral dimension. The binning process addstogether photons from adjacent pixels in the detector array and wasperformed by the shift register of the EMCCD Imaging Device 1A. Thisproduced a reduced number of pixels to be digitized by the 16-bit A/DPCI board for the computer 7 to process. Reducing total pixel readouttime decreased the acquisition time of each line-scan image, whichallowed higher image acquisition speed for the EMCCD Imaging Device 1A.Because the useful spectrum of light did not span the entire width ofthe EMCCD Imaging Device 1A, the first 20 and last 53 spectral channelswere discarded, resulting in a final line-scan image size of 512×55pixels for hyperspectral imaging.

The next step in the calibration process was physical alignment of thespectrograph 1C to ensure uniform waveband dispersal across the spectraldimension for each spatial pixel. This alignment was ascertained byexamining the spectral dispersal of the 55 wavebands for each of the 512spatial pixels for a line-scan image: the highest intensity value amongall 55 wavebands should occur at the same spectral coordinate for eachof the 512 spatial pixels (FIG. 2, Box 2.3).

The next step in the calibration process was spectral wavebandcalibration that identified each spectral channel with a specificwavelength. A neon-mercury calibration lamp (Oriel Instruments,Stratford, Conn.) provided spectral reference peaks (FIG. 2, Box 2.4)for calibration using the following second-order polynomial regression:

λ=0.01×n _(c) ²+6.03×n _(c)+393.70

where λ is the wavelength in nm and n_(c) is the spectral channel number(FIG. 2, Box 2.5). The spectral range of the line-scan images began at399.94 nm for the first channel and ended at 750.42 nm for the 55^(th)channel.

Following system calibration, the hyperspectral/multispectral imagingsystem 10 was ready to be used for the acquisition of referenceline-scan images. Prior to acquiring hyperspectral chicken images,acquisition of a white reference image was performed using a 99% diffusereflectance standard (Spectralon, LabSphere, Inc., North Sutton, N.H.)illuminated by lighting system 2; acquisition of a dark reference imagewas performed by acquiring an image with the lens covered by anon-reflective opaque black fabric (FIG. 3, Box 3.1). These referenceline-scan images were used to calculate the pixel-based relativereflectance for raw hyperspectral line-scan images as follows:

$I = \frac{I_{0} - D}{W - D}$

where I is the relative reflectance, I₀ is the raw reflectance, D is thedark reference, and W is the white reference (FIG. 3, Box 3.3).

Following acquisition of raw hyperspectral line-scan images of chickens(FIG. 3, Box 3.2) and conversion to relative reflectance images (FIG. 3,Box 3.3), analysis of the hyperspectral relative reflectance imagesbegan with removal of the background. A relative reflectance thresholdvalue of 0.1 was set for the 620 nm waveband. For any spatial pixel inthe hyperspectral reflectance image, the pixel was identified as abackground pixel if its reflectance at 620 nm was lower than the 0.1threshold value. The value of the relative reflectance for every pixelidentified as a background pixel was re-assigned to be zero, thusremoving these pixels from further image analysis (FIG. 3, Box 3.3).

The background-removed relative reflectance line-scan images werecompiled to form hyperspectral image cubes of entire wholesome andunwholesome chicken carcasses (FIG. 3, Box 3.4). Using MATLAB software,(MathWorks, Natick, Mass.), the hyperspectral chicken images were thenanalyzed to optimize the spatial Region of Interest (ROI) within thechicken images (FIG. 3, Box 3.5). The optimized ROI was one whichprovided the greatest spectral difference between averaged wholesomepixels and averaged unwholesome pixels across all 55 wavebands, whichwas obtained as follows: Within a bird image, the potential ROI areaspanned from an upper border across the breast of the bird to a lowerborder at the lowest non-background spatial pixel in each line scan, orto the last (512^(th)) spatial pixel if there were no background pixelspresent at the lower edge of the image. The average relative reflectancespectrum was calculated across all ROI pixels for all wholesome chickenimages, and the average relative reflectance spectrum was calculatedacross all ROI pixels for all unwholesome chicken images. The differencespectrum between the wholesome and unwholesome average spectra wascalculated. This calculation was performed for potential ROIs of varyingsize, as defined by the number of ROI pixels and their verticalcoordinate locations within each line-scan, to optimize the ROI size andlocation by selecting the ROI that produced the greatest maximum valuein its difference spectrum. Using the optimized ROI, the wavebandcorresponding to the greatest spectral difference between averagedwholesome chicken pixels and averaged unwholesome chicken pixels wasidentified as a key waveband for differentiation of wholesome andunwholesome chicken carcasses by relative reflectance intensity (FIG. 3,Box 3.6). Again using the optimized ROI, the average wholesome andaverage unwholesome spectra were analyzed and potential two-wavebandratios were identified as several ratios using wavebands at which theaverage wholesome and average unwholesome chicken pixel spectra showedlocal maxima and local minima. The value of each potential band ratiowas calculated for the average wholesome chicken pixels and for theaverage unwholesome chicken pixels. The two-waveband ratio showing thegreatest difference in ratio value between average wholesome and averageunwholesome chicken pixels was identified for use in differentiatingwholesome and unwholesome chicken carcasses (FIG. 3, Box 3.7).Multispectral imaging inspection used the key wavelength and thetwo-waveband ratio to differentiate between wholesome and unwholesomechicken carcasses.

Effective multispectral imaging inspection of wholesome and unwholesomechicken carcasses on a processing line required the capacity fordetecting individual bird carcasses, classifying the condition of thechicken carcass, and generating a corresponding output useful forprocess control, at speeds compatible with online processing lineoperations. LabVIEW 8.0 (National Instruments Corp., Austin, Tex.) wasused to control hyperspectral/multispectral imaging system 10 to performthe tasks required for multispectral inspection of chicken carcasses ona poultry processing line. The line-by-line mode of operation was thebasis of the following algorithm that was developed to detect the entryof a bird carcass into the IFOV.

FIG. 4 shows the line-by-line algorithm for multispectral inspection todetect and classify wholesome and unwholesome chicken carcasses on aprocessing line. First, a line-scan image was acquired that containsonly raw reflectance values at the two key wavebands needed forintensity and ratio differentiation, the raw reflectance data wasconverted into relative reflectance data, and background pixels wereremoved from the image (FIG. 4, Box 4.1). The line-scan image waschecked for the presence of the SP (Starting Point) of a new bird (FIG.4, Box 4.2); if no SP was present, no further analysis was performed forthis line-scan image and a new line-scan image was acquired. If theline-scan was found to contain an SP, then the ROI pixels were located(FIG. 4, Box 4.3) and the D_(o) value was calculated for each pixel inthe ROI of the line-scan image (FIG. 4, Box 4.4). With each newline-scan image acquired (FIG. 4, Box 4.5), the ROI pixels were located,and the decision output value of D_(o) was calculated for each pixel,until the EP (Ending Point) was detected (FIG. 4, Box 4.6), indicatingno additional line-scan images to be analyzed for the bird carcass. Theaverage D_(o) value for the bird was calculated (FIG. 4, Box 4.9) andcompared to the threshold value (FIG. 4, Box 4.10) for the finaldetermination of wholesomeness or unwholesomeness for the bird carcass(FIG. 4, Boxes 4.11 and 4.12).

With the acquisition of each new line-scan image at the start of thedetection algorithm, (FIG. 4, Box 4.1), the relative reflectance at 620nm was examined for each of the first (uppermost) 256 pixels of theline-scan image. The value of the relative reflectance at 620 nm wasalways at a low-intensity (below 0.1) for these pixels when there was nochicken carcass present in the IFOV. When the relative reflectance at620 nm increased above 0.1 for any single pixel among the uppermost 256pixels in the line-scan image, this indicated that a chicken carcass hasentered the IFOV. This indication assumed that the inverted chickencarcass was correctly hung from the processing line shackle by both legsand that the entry of the first leg into the IFOV is triggering thedetection. The detection algorithm examined only the uppermost 256pixels in order to disregard carcass wings which were always overlappedbetween adjacent carcasses on the processing line. After detecting aline-scan image with a single pixel among the uppermost 256 exhibitingrelative reflectance greater than 0.1 at 620 nm, the subsequentline-scan images were monitored as additional pixels within the 256pixels began showing relative reflectance values greater than 0.1 (FIG.4, Box 4.2). Between the first detected pixel and the 256^(th) pixel,pixels below the first detected pixel began increasing in relativereflectance as the chicken continues to move across the field of view.There would eventually be a line-scan image with one (or several)low-intensity pixels left that was located below the first detectedpixel, and above or at the 256^(th) pixel, which was immediatelyfollowed by another line-scan in which the previous line-scan's lastlow-intensity pixel(s) had increased above 0.1. The last low-intensitypixel, or the pixel in the center of the last contiguous group ofremaining low-intensity pixels, was identified as the Starting Point(SP) of the bird carcass and represented the junction between the thighand the abdomen on the leading edge of the carcass.

Similar to the above algorithm, the following algorithm was developed todetect the last relevant line-scan image for each bird as it passedthrough the IFOV (FIG. 4, Box 4.6). After the SP was detected, eachsubsequent line-scan image was analyzed to determine if the relativereflectance intensity at 620 nm for the pixel matching the verticalcoordinate of the SP was above or below 0.1 When a line-scan image wasacquired for which that pixel had a relative reflectance intensity at620 nm that was below 0.1, this pixel was identified as the Ending Point(EP) of the bird carcass, indicating that the main body of the bird hadalready passed through the IFOV and no further line-scans should beanalyzed for that specific bird carcass.

After the initial identification of the SP for a bird carcass, theline-scan image containing the SP and subsequent line-scan images up tothe one containing the EP were analyzed, line-by-line (FIG. 4, Boxes 4.3through 4.8), using the following algorithm to classify the birdcarcass. For each line-scan image, fuzzy logic membership functions wereused to produce two decision outputs for each non-background pixel inthe line-scan image that was located within the ROI, using the ROI andwaveband parameters previously determined through hyperspectral imaginganalysis. For each pixel, two fuzzy logic membership functions were usedto generate wholesome and unwholesome fuzzy membership values w₁ and u₁,corresponding to wholesome and unwholesome chickens, from the keywavelength reflectance intensity value for that pixel. Two additionalfuzzy logic membership functions were used to generate wholesome andunwholesome fuzzy membership values w₂ and u₂, corresponding towholesome and unwholesome chickens, from the ratio value for that pixel.The fuzzy inference engine executed a min-max operation (Chao, K., etal., Appl. Eng. in Agric., 15(4): 363-369 (1999)) to obtain a decisionoutput D_(o) for each pixel based on the n membership functions asfollows, where n is the number of criteria input used (in this case,n=2):

D_(o)=max[min{w₁ . . . w_(n)},min{u₁ . . . u_(n)}]

For each pixel, the value of D_(o) was in the range between 0 and 1,where 0 indicates 100% possibility of wholesomeness and 1 indicated 100%possibility of unwholesomeness. When the EP for that bird carcass wasencountered, the average D_(o) value for all ROI pixels for that birdwas calculated (FIG. 4, Box 4.9). The bird carcass was identified asbeing unwholesome if the average D_(o) value was greater than 0.6;otherwise the chicken carcass was identified as being wholesome (FIG. 4,Boxes 4.10, 4.11, 4.12).

The hyperspectral/multispectral imaging inspection system demonstratedclassification accuracies greater than 90% on commercial processinglines which were operated at speeds of 70 bpm and 140 bpm. Currentprocessing operations in U.S. poultry plants are allowed to run atspeeds up to 140 bpm.

The following examples are intended only to further illustrate theinvention and are not intended to limit the scope of the invention whichis defined by the claims.

EXAMPLES Example 1

Calibration of the imaging system 10 was conducted for the acquisitionof hyperspectral chicken images on a commercial processing line.Following the cooling of the EMCCD detector to the necessary −70° C.operating temperature, spectral images were acquired using amercury-neon pen lamp. With 1 by 4 binning (4× binning in the spectraldimension), the mercury and neon reference peaks shown in FIG. 5 wereutilized for spectral calibration; the mercury peaks at 435.84 and546.07 nm were found to correspond to the 8^(th) and 25^(th) bands,respectively, and neon peaks at 614.31, 640.23, 703.24, and 724.52 nmcorresponded to the 35^(th), 39^(th), 49^(th), and 52^(nd) bands,respectively. FIG. 6 shows a plot of the second-order polynomialregression that was calculated from the mercury and neon spectral peaksto calibrate the spectral axis: wavelength (nm)=0.01X ²+6.03X+393.70(r²=0.9999)

where X is the spectral band number. The imaging spectrum ranged from399.94 nm (the first band) to 750.42 nm (the 55^(th) band) with anaverage bandwidth of 6.02 nm. The distance between the lens and IFOVtarget area was 914 mm, with the LED line lights illuminating the IFOVtarget area from a distance of 214 mm. The IFOV spanned 177.8 mm, whichtranslated into 512 spatial pixels, with each pixel representing an areaof 0.12 mm².

Example 2

Using the calibration from Example 1 above, hyperspectral images wereacquired using imaging system 10 for 5549 wholesome chicken carcassesand 93 unwholesome chicken carcasses on a 140 bpm commercial processingline, for analysis to optimize the ROI size and location and todetermine the key intensity waveband and ratio wavebands to be used foronline inspection. The wholesome or unwholesome condition of the birdson the line was identified by an FSIS veterinarian who observed thebirds before they passed through the illuminated IFOV, where the imagingsystem acquired 55-band hyperspectral data for the chicken carcasses.FIG. 7 shows example images, at four bands, of chickens on theprocessing line, including one unwholesome chicken (fifth from the left)among the series in the image. The images shown were compiled usingimage data from the 1^(st), 30^(th), 36^(th), and 55^(th) spectralbands, corresponding to 400 nm, 580 nm, 620 nm, and 750 nm.

The hyperspectral images were analyzed to optimize the ROI size andlocation and the key wavebands for differentiation by reflectanceintensity and by waveband ratio. FIG. 8 shows a contour image of twoexamples of chicken carcasses with the SP and EP marked and connected bya line on each. The possible size and location of the ROI is describedby parameters m and n, which extended below the SP-EP line. The valuesof m and n indicated, by percentage of the pixel length between theSP-EP line and the furthest non-background pixel below the SP-EP line,the location of the upper and lower ROI borders. The possible locationsof the upper ROI border ranged between a 10% and 40% distance below theSP-EP line, and the possible locations of the lower ROI border rangebetween a 60% and 90% distance below the SP-EP line.

For each possible ROI, the average spectrum across all ROI pixels fromthe 5549 wholesome chicken carcasses, and the average spectrum acrossall ROI pixels from the 93 unwholesome chicken carcasses, werecalculated. The difference between the average wholesome and averageunwholesome value at each of the 55 bands was calculated and their rangefor each possible ROI is shown in FIG. 9. Because the 40%-60% ROI showedthe range with the greatest difference values between the averagewholesome and unwholesome spectra, this ROI was considered the optimizedROI to be used for multispectral inspection. As shown in FIG. 10, the30^(th) band showed the greatest difference between the averagewholesome and the average unwholesome spectra from among all 55 bandsfor the optimized ROI; this band, corresponding to 580 nm, was selectedas the key waveband to be used for intensity-based differentiation ofwholesome and unwholesome chicken carcasses.

FIG. 11 shows the average wholesome and average unwholesome chickenspectra, marked with the wavebands that were investigated fordifferentiation of wholesome and unwholesome chicken carcasses by atwo-waveband ratio. The average ratio values were calculated for threepossible two-waveband ratios:

W ₄₄₀ /W ₄₆₀ −U ₄₄₀ /U ₄₆₀=0.003461

W ₅₀₀ /W ₅₄₀ −U ₅₀₀ /U ₅₄₀=0.038602

W ₅₈₀ /W ₆₂₀ −U ₅₈₀ /U ₆₂₀=0.115535

The last ratio, using the 580 nm and 620 nm wavebands, showed thegreatest difference between the average wholesome and averageunwholesome chicken spectra and was thus selected for use indifferentiation by two-waveband ratio. FIG. 12 shows plots of the meanand standard deviation for the 580 nm key waveband and for the keywaveband ratio using 580 nm and 620 nm, for wholesome and unwholesomechickens in the hyperspectral image data set.

Example 3

The optimized ROI and key wavebands determined in Example 2 above wereused for multispectral inspection of over 100,000 chickens on a 140 bpmprocessing line during two 8-hour shifts at a commercial poultry plant.FIG. 14 shows examples of chicken images highlighting the ROI that wasused for online inspection. The inspection program specificallydetermined the 40%-60% ROI for each bird, which was clearly affected bythe size and position of the bird. The ROI was a regular rectangulararea for a bird whose body extended past the lower edge of the image,such as the first bird in FIG. 14. For other birds, the presence ofbackground pixels near the lower edge of the image resulted inirregularly shaped ROIs. FIG. 13 shows a scatter plot for the chickensinspected during the first shift, by the number of ROI pixels and thenumber of ROI lines for each bird. For 99% of the birds imaged duringthe first 8-hour inspection shift, imaging system 10 acquired between 15and 40 ROI line-scan images, resulting in 1000-3500 ROI pixels forclassification analysis. A very small number of data points in FIG. 13showed an unusually high number of ROI lines and ROI pixels, or a highnumber of ROI lines with very few ROI pixels. These data points resultedfrom occasional occurrences of birds that were not correctly hung orthat were unusually positioned, such as being hung by one leg or beinghung by two legs but on separate shackles, that may have prevented cleardistinction between individual adjacent birds by the imaging system orresulted in an elevated position within the IFOV.

Table 1 below shows the mean and standard deviation values for relativereflectance at 580 nm for wholesome and unwholesome birds in three datasubsets drawn from the hyperspectral data analysis using the 40%-60% ROIin Example 2 and each of the two inspection shifts in Example 3. Table 2shows the mean and standard deviation values for the two-waveband ratiousing 580 nm and 620 nm for wholesome and unwholesome birds for the samethree data subsets. Paired t-tests showed no significant differences(P=0.05) between the three data sets for the wholesome means, andsimilarly no significant difference between the three data sets for theunwholesome means. This demonstrates that when thehyperspectral/multispectral imaging system 10 is appropriately andconsistently operated to maintain proper distance and illuminationconditions, hyperspectral data collected by the system can beappropriately used for multispectral inspection conducted at differenttimes and locations.

TABLE 1 Mean and standard deviation values for reflectance intensity at580 nm for wholesome and unwholesome chicken images WholesomeUnwholesome Mean SD Mean SD Hyperspectral Analysis 0.378 0.088 0.2430.076 Inspection Shift 1 0.419 0.115 0.253 0.069 Inspection Shift 20.398 0.083 0.253 0.075

TABLE 2 Mean and standard deviation values for two-waveband ratio using580 nm and 620 nm for wholesome and unwholesome chicken images WholesomeUnwholesome Mean SD Mean SD Hyperspectral Analysis 0.948 0.037 0.9040.052 Inspection Shift 1 0.958 0.033 0.918 0.048 Inspection Shift 20.941 0.038 0.919 0.048

For multispectral classification, fuzzy logic membership functions werebuilt based on the mean and standard deviation values for the 580 nm keywaveband from the hyperspectral analysis data subset, and on the meanand standard deviation values for the 580 nm and 620 nm two-wavebandratio, again from the hyperspectral analysis data subset. FIG. 15 showsthe structure of the fuzzy logic membership functions. These functionswere used to classify each ROI pixel within an image as either wholesomeor unwholesome, by using each pixel's 580 nm intensity value at 580 nmand its ratio value as inputs to obtain a decision output value D_(o)between 0 and 1. The average D_(o) value for a bird was used todetermine a wholesome or unwholesome assignment by comparison with athreshold value. FIG. 16 first shows a masked image of nine chickenswith all ROI pixels highlighted for each chicken (top), and then anotherimage highlighting only those ROI pixels that were classified aswholesome pixels (bottom), i.e., D_(o) values of individual pixels wereeach compared to the 0.6 threshold value. The fourth chicken from theleft is an unwholesome bird and all of its ROI pixels were identified asunwholesome, consequently not appearing in the second image (bottom).

FIGS. 17 and 18 show scatterplots of the imaging system's decisionoutputs against the number of ROI pixels for each chicken imaged duringinspection shifts 1 and 2. The total numbers of wholesome andunwholesome chickens identified by the system are shown in Table 3below, compared with numbers drawn from FSIS tally sheets created bythree inspection stations on the same processing line during those twoinspection shifts. Although direct bird-to-bird comparison between theimaging inspection system and the inspectors was not possible,surprisingly the percentages indicated that the relative numbers ofwholesome and unwholesome identified by the imaging inspection systemand by the processing line inspectors were not significantly different.

TABLE 3 Wholesome and unwholesome birds identified during inspectionshifts by processing line inspectors and by the imaging inspectionsystem Line inspectors Imaging inspection system Wholesome UnwholesomeTotal Wholesome Unwholesome Total Shift 53563 84 53647 45305 288 45593 1(99.84%) (0.16%) (100%) (99.37%) (0.63%) (100%) Shift 64972 71 6504360922 98 61020 2 (99.89%) (0.11%) (100%) (99.84%) (0.16%) (100%)

A veterinarian also conducted several periods of system verification,each lasting approximately 30 to 40 minutes. The veterinarian conductedbird-by-bird observation of chicken carcasses immediately before theyentered the IFOV of the imaging system. The imaging system output wasobserved for agreement with the veterinarian's identifications. Theveterinarian observed 16,174 wholesome birds and 43 unwholesome birdsover 4 verification periods during inspection shift 1. Of these birds,the imaging system surprisingly incorrectly identified only 118wholesome birds (99.27% correct) and 2 unwholesome birds (95.35%correct). The veterinarian observed 27,626 wholesome birds and 35unwholesome birds over 6 verification periods during inspection shift 2.Of these birds, the imaging system surprisingly incorrectly identifiedonly 46 wholesome birds (99.83% correct) and 1 unwholesome bird (97.14%correct). These results, together with the percentages listed in Table3, strongly suggest that the imaging inspection system can performsuccessfully on a commercial poultry processing line.

For multispectral inspection as conducted on a 140 bpm processing lineas was performed for this example, the imaging system acquired about 30to 40 line-scan images between the SP and EP for each chicken inspected.Previous testing of the imaging system on a 70 bpm processing linedemonstrated similar performance in identification of wholesome andunwholesome birds with the analysis of about 70-80 line-scan images foreach chicken. Because the unwholesome birds exhibit a systemicunwholesome condition affecting the entire body of the bird, thisline-scan imaging system is able to identify such birds at even higherspeeds; on a 200 bpm processing line, for example, the system wouldperform similarly in identifying wholesome and unwholesome birds byanalyzing about 20-25 line-scan images for each chicken.

All of the references cited herein, including U.S. Patents, areincorporated by reference in their entirety. Also incorporated byreference in their entirety are the following references: Chao et al,Applied Engineering in Agriculture, 18(1): 78-84 (2002); Chao et al.,Proc. SPIE, 6381: 63810V1-63810V11 (2006); Chao et al., J. Sensing andInstrumentation for Food Quality and Safety, 1(2): 62-71 (2007);Lawrence et al, Trans. ASAE, 46(2): 513-521 (2003); Park et al, Trans.ASAE, 45(6): 2017-2026 (2003); Park et al., J. Food ProcessingEngineering, 27(5): 311-327 (2005); Yang et al., J. Food Engineering,69(2): 225-234 (2005); Yang et al., Proc. SPIE, 6381: 63810Y1-63810Y10(2006); Yang et al., Trans. ASAE, 49(1): 245-257 (2006); U.S. Pat. No.6,587,575.

Thus, in view of the above, the present invention concerns (in part) thefollowing:

An imaging system for food safety wholesomeness inspection of freshlyslaughtered chicken carcasses on a processing line (for acquisition andprocessing of hyperspectral/multispectral reflectance images of freshlyslaughtered chicken carcasses on a processing line for food safetyinspection), comprising (or consisting essentially of or consisting of):

a means for obtaining both hyperspectral and multispectral images (offreshly slaughtered chicken carcasses on a processing line), and

a data acquisition/processing unit operatively connected to said meansfor obtaining hyperspectral and multispectral images

(wherein the system is capable of hyperspectral/multispectral imaging todetect individual chicken carcasses on a processing line and todetermine the wholesome or unwholesome condition of a chicken carcass).

The above imaging system wherein said system further comprises alighting system (operatively connected to said means for obtaininghyperspectral and multispectral images).

The above imaging system wherein said system further comprises a meansof creating a dark imaging background.

The above imaging system wherein said means for obtaining hyperspectraland multispectral images comprises (only one of each):

(an imaging device utilizing) an electron-multiplying charge-coupleddevice detector,

a (14-bit and/or 16-bit) digitizer operatively connected to saidelectron multiplying charge-coupled device detector (wherein saiddigitizer has a pixel-readout rate in the range of approximately 10 MHzto approximately 30 MHz),

a line-scan spectrograph operatively connected to saidelectron-multiplying charge-coupled device detector, and

a lens assembly operatively connected to said line-scan spectrograph.

The above imaging system wherein said means for obtaining hyperspectraland multispectral images does not include a shutter.

The above imaging system wherein said lighting system comprisescontinuous wave light sources for reflectance imaging.

The above imaging system wherein said lighting system comprises at leasttwo continuous wave light sources for reflectance imaging to provideillumination spanning at least 400 nm to 800 nm in thevisible/near-infrared spectrum with a total intensity of at least 10,000lux (lumens/m²).

The above imaging system wherein said data acquisition/processing unitis encoded with algorithms for hyperspectral/multispectral imageacquisition, analysis, and classification.

A method of determining parameters for multispectral inspection offreshly slaughtered chicken carcasses to identify wholesome andunwholesome chicken carcasses (by analyzing a set of hyperspectralimages of wholesome and unwholesome chicken carcasses), comprising (orconsisting essentially of or consisting of):

-   -   (a) optimization of the location and size of a Region of        Interest within individual bird images for identification of        wholesome and unwholesome chicken carcasses by spectral        analysis;    -   (b) selection of key wavebands based on reflectance intensity at        a single waveband and on ratio of reflectance intensities at two        wavebands for input into a fuzzy logic classifier to identify        wholesome and unwholesome chicken carcasses wavebands;    -   (c) construction of fuzzy logic membership functions for        identifying wholesome and unwholesome chickens, by use of the        following algorithm:        -   (i) specify the size and location of potential Region of            Interest selections across the breast area of chicken            carcass images relative to vertical pixel coordinates within            the images, for which said pixel coordinates are defined by            percentage values of the distance extending from a            horizontal line across the chicken breast area towards the            chicken neck area to the furthest non-background pixel;        -   (ii) for each potential Region of Interest selection,            calculate the average reflectance spectrum calculated using            all Region of Interest pixels for all wholesome chickens in            the set of hyperspectral images;        -   (iii) for each potential Region of Interest selection,            calculate the average reflectance spectrum calculated using            all Region of Interest pixels for all unwholesome chickens            in the set of hyperspectral images;        -   (iv) for each potential Region of Interest selection,            calculate the difference spectrum between the average            wholesome spectrum and average unwholesome spectrum, and            note the maximum difference value that occurs for each            potential Region of Interest;        -   (v) compare the maximum difference values from all potential            Regions of Interest to select the Region of Interest that            resulted in the greatest maximum difference value as the            optimized Region of Interest to use for multispectral            identification of wholesome and unwholesome chicken            carcasses;        -   (vi) select the waveband corresponding to the greatest            maximum difference value of the optimized Region of Interest            as the key wavelength to use for multispectral            identification of wholesome and unwholesome chickens based            on reflectance intensity;        -   (vii) using the optimized Region of Interest calculate the            mean and standard deviation of reflectance intensity at the            key wavelength from (vi) for wholesome chickens and            calculate the mean and standard deviation of reflectance            intensity values at the key wavelength for unwholesome            chickens;        -   (viii) specify potential pairs of key wavebands selected            according to local maxima and minima in the difference            spectrum of the optimized Region of Interest;        -   (ix) calculate the band ratio value for each potential pair            of key wavebands for the average wholesome Region of            Interest reflectance spectrum calculated in (ii) and the            average unwholesome Region of Interest reflectance spectrum            calculated in (iii);        -   (x) select the waveband pair corresponding to the greatest            difference between band ratio values for wholesome and            unwholesome as the key waveband pair to use for            multispectral identification of wholesome and unwholesome            chicken carcasses based on ratio value;        -   (xi) using the optimized Region of Interest calculate the            mean and standard deviation of the two-waveband ratio            from (x) for wholesome chickens and calculate the mean and            standard deviation of the two-waveband ratio for unwholesome            chickens; and        -   (xii) construct fuzzy logic membership functions based on            the mean and standard deviation values for key wavelength            (intensity) and two-waveband ratio values for wholesome and            unwholesome chickens.

The above method wherein a set of hyperspectral images of freshlyslaughtered wholesome and unwholesome chicken carcasses is acquired withthe use of an imaging system with at least one electron-multiplyingcharge-coupled device detector operatively connected to both aspectrograph and a lens assembly.

The above method wherein a set of hyperspectral images of freshlyslaughtered wholesome and unwholesome chicken carcasses is acquired withthe use of a lighting system providing continuous wave illuminationspanning at least 400 nm to 800 nm in the visible/near-infrared regionof the electromagnetic spectrum of at least 10,000 lux (lumen/m²) and ameans of providing a dark imaging background.

A method of multispectral inspection of freshly slaughtered chickencarcasses to identify wholesome and unwholesome chicken carcasses on achicken processing line, comprising (or consisting essentially of orconsisting of):

-   -   (a) continuous real-time acquisition of line-scan images of        freshly slaughtered chickens on a commercial chicken processing        line (operated at speeds between about 70 to about 200 birds per        minute (e.g., 70-200 bpm);    -   (b) real-time analysis of individual line-scan images to        identify the presence and entrance of the leading edge of a        chicken into the linear field of view of the imaging inspection        system;    -   (c) real-time analysis of individual line-scan images to locate        Region of Interest pixels for individual chickens;    -   (d) real-time calculation of decision output values for Region        of Interest pixels in individual line-scan images;    -   (e) real-time analysis of individual line-scan images to        identify the exit of the trailing edge of a chicken from the        linear field of view of the imaging inspection system; and    -   (f) calculation of average decision output values to identify        chickens as being wholesome or unwholesome by comparison to a        threshold value, by use of the following algorithm:        -   (i) acquire a line-scan image and analyze the line-scan            image to determine if the starting point coordinate of a            chicken has been assigned, if no starting point coordinate            has been assigned then repeat acquisition and analysis until            a line-scan image is encountered for which a starting point            coordinate has been assigned;        -   (ii) locate the Region of Interest pixels within the            line-scan image and calculate the decision output value for            each Region of Interest pixel by using the reflectance            intensity and waveband ratio values at the key wavebands as            inputs to the fuzzy logic membership functions for            classification, acquire a new line-scan image if no ending            point coordinate has been assigned, repeat location of the            Region of Interest and calculation of decision output values            for each Region of Interest pixel for each new line-scan            image until a line-scan image is encountered for which an            ending point coordinate has been assigned;        -   (iii) calculate the average decision output value for the            chicken across all Region of Interest pixels using values            calculated in (ii); and        -   (iv) compare the average decision output value with the            threshold value to identify an individual bird as either            wholesome or unwholesome.

The above method wherein real-time analysis of individual line-scanimages to identify the presence and entrance of the leading edge of achicken into the linear field of view of the imaging inspection systemis performed by using the following algorithm:

-   -   (a) examine the 1-dimensional data array whose indices        correspond to the uppermost 256 pixels of the line-scan image        with 1 at the top of the line-scan image and which contains the        relative reflectance values at the 620 nm waveband of the        uppermost 256 pixels, if the array contains only values        corresponding to background pixels having relative reflectance        below 0.1 then continue examining subsequent line-scan images        until the first non-background pixel or group of pixels is        detected within the array; when any non-background pixels having        relative reflectance greater than 0.1 are detected, indicating        that a new chicken has entered the linear field of view, note        the corresponding index of the first uppermost such pixel and        assign this index as the top reference coordinate, if the value        of the array at the last index does not correspond to a        background pixel then note the index of the last lowermost        background pixel in the array and assign this index as the        bottom reference coordinate;    -   (b) for the subsequent line-scan image, examine only the array        values at the indices corresponding to and including the top        reference coordinate and the bottom reference coordinate, within        these indices find the index of the first uppermost background        pixel and the last lowermost background pixel and reassign these        indices to be the top reference coordinate and bottom reference        coordinate respectively;    -   (c) for each subsequent line-scan image continue searching for        first and last background pixels between the top reference        coordinate and bottom reference coordinate and then re-assigning        the reference coordinates to the corresponding indices; and    -   (d) when a line-scan image is found for which there are no        background pixels occurring between the top reference coordinate        and the bottom reference coordinate, check whether the top and        bottom reference coordinates are assigned to the same index        value, if they are the same then assign the vertical coordinate        of the corresponding image pixel to be the starting point pixel,        if they are not the same then assign the median of the two        indices to be the starting point for the current chicken being        imaged.

The above method wherein real-time analysis of individual line-scanimages to locate Region of Interest pixels for individual chickens isperformed by using the following algorithm:

-   -   (a) if the starting point has been assigned for the current        chicken being imaged, examine the line-scan image and find the        lowermost non-background pixel within the line-scan image which        may coincide with the lowermost pixel of the line-scan image if        there are no background pixels that the bottom of the line-scan        image;    -   (b) find the number of pixels between and including the starting        point coordinate and the lowermost non-background pixel and        consider this the reference distance; and    -   (c) with the previously determined values of parameters m and n,        each in the range between 0% and 100%, select all pixels within        the line-scan image that occur between m % of the reference        distance and n % of the reference distance, where the starting        point coordinate is at 0% and the lowermost non-background pixel        is the at 100%, these selected pixels comprise the ROI for this        line-scan image.

The above method wherein real-time analysis of individual line-scanimages to identify the exit of the trailing edge of a chicken from thelinear field of view of the imaging inspection system is performed byusing the following algorithm:

-   -   (a) if the starting point has been assigned for the current        chicken being imaged, examine the relative reflectance value at        620 nm of the line-scan image at the starting point coordinate;    -   (b) if the value corresponds to a non-background pixel, relative        reflectance greater than 1.0, do not assign a value to be the        ending point coordinate; and    -   (c) if the value corresponds to a background pixel, relative        reflectance less than 0.1, then assign the starting point        coordinate to be the ending point coordinate, indicating that        the previous line-scan image was the last line-scan to be        analyzed for the current chicken being imaged and no additional        line-scans are to be analyzed.

The above method wherein real-time calculation of decision output valuesfor each Region of Interest pixel in the line-scan images is performedusing a fuzzy logic classifier defined by the following equation:

D_(o)=max[min{w₁,w₂}, min{u₁,u₂}]

wherein w₁ and u₁ are fuzzy membership values for the pixel based on thereflectance intensity at the key wavelength, w₂ and u₂ are fuzzymembership values based on the two-waveband ratio, min indicates aminima operation that selects the smaller of the two values, maxindicates a maxima operation that selects the larger of the two values,and D_(o) is the decision output value for the pixel.

A process for automated online inspection of freshly slaughtered chickencarcasses on a processing line to identify wholesome and unwholesomechickens, comprising (or consisting essentially of or consisting of):

(a) illuminating said chicken carcasses with a source of electromagneticradiation having a predetermined spectral content,

(b) detecting radiation from said source reflected by said chickencarcasses in each of two key wavelengths, λ₁ and λ₂, using an imagingsystem that correlates radiation intensity at each of the two keywavelengths with spatial pixels of the images of said chicken carcasses,

(c) identifying the entrance and exit of each of said chicken carcassesthrough the field of view of the imaging system,

(d) identifying selected areas of each image of said chicken carcassesfor which the values of reflected radiation intensity will be used incalculations to identify wholesomeness or unwholesomeness,

(e) calculating the ratio of the radiation intensity at λ₁ divided bythe radiation intensity at λ₂ for each pixel in the selected areas ofeach image,

(f) calculating decision output values for each image pixel using afuzzy logic classifier, and

(g) generating an identification of being wholesome or unwholesome foreach of said chicken carcasses based on the comparison of the averagedecision output for the selected area of each chicken image with adecision-making threshold value.

The above process wherein λ₁ is from about 570 nm to about 590 nm (e.g.,570-590 nm) and 2 is from about 610 nm to about 630 nm (e.g., 610-630nm).

The above process wherein λ₁ is about 580 nm and λ₂ is about 620 nm.

The above process wherein λ₁ is 580 nm and λ₂ is 620 nm.

A process for automated online inspection of freshly slaughtered chickencarcasses on a processing line to identify wholesome and unwholesomechickens, comprising (or consisting essentially of or consisting of)following the procedure in FIG. 4.

A method of determining parameters for multispectral inspection offreshly slaughtered chicken carcasses to identify wholesome andunwholesome chicken carcasses (by analyzing a set of hyperspectralimages of wholesome and unwholesome chicken carcasses), comprising (orconsisting essentially of or consisting of) following the procedure inFIG. 3.

Other embodiments of the invention will be apparent to those skilled inthe art from a consideration of this specification or practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with the true scope and spiritof the invention being indicated by the following claims.

1. An imaging system for food safety wholesomeness inspection of freshlyslaughtered chicken carcasses on a processing line, comprising: a meansfor obtaining both hyperspectral and multispectral images, and a dataacquisition/processing unit operatively connected to said means forobtaining hyperspectral and multispectral images, wherein the system iscapable of hyperspectral/multispectral imaging to detect individualchicken carcasses on a processing line and to determine the wholesome orunwholesome condition of a chicken carcass.
 2. The imaging system ofclaim 1 wherein said system further comprises a lighting system.
 3. Theimaging system of claim 1 wherein said means for obtaining hyperspectraland multispectral images comprises: an electron-multiplyingcharge-coupled device detector, a digitizer operatively connected tosaid electron multiplying charge-coupled device detector, a line-scanspectrograph operatively connected to said electron-multiplyingcharge-coupled device detector, and a lens assembly operativelyconnected to said line-scan spectrograph.
 4. The imaging system of claim2 wherein said lighting system comprises at least two continuous wavelight sources for reflectance imaging to provide illumination spanningat least 400 nm to 800 nm in the visible/near-infrared spectrum with atotal intensity of at least 10,000 lux (lumens/m²).
 5. The imagingsystem of claim 1 wherein said data acquisition/processing unit isencoded with algorithms for hyperspectral/multispectral imageacquisition, analysis, and classification.
 6. A method of determiningparameters for multispectral inspection of freshly slaughtered chickencarcasses to identify wholesome and unwholesome chicken carcasses,comprising: (a) optimization of the location and size of a Region ofInterest within individual bird images for identification of wholesomeand unwholesome chicken carcasses by spectral analysis; (b) selection ofkey wavebands based on reflectance intensity at a single waveband and onratio of reflectance intensities at two wavebands for input into a fuzzylogic classifier to identify wholesome and unwholesome chicken carcasseswavebands; (c) construction of fuzzy logic membership functions foridentifying wholesome and unwholesome chickens, by use of the followingalgorithm: (i) specify the size and location of potential Region ofInterest selections across the breast area of chicken carcass imagesrelative to vertical pixel coordinates within the images, for which saidpixel coordinates are defined by percentage values of the distanceextending from a horizontal line across the chicken breast area towardsthe chicken neck area to the furthest non-background pixel; (ii) foreach potential Region of Interest selection, calculate the averagereflectance spectrum calculated using all Region of Interest pixels forall wholesome chickens in the set of hyperspectral images; (iii) foreach potential Region of Interest selection, calculate the averagereflectance spectrum calculated using all Region of Interest pixels forall unwholesome chickens in the set of hyperspectral images; (iv) foreach potential Region of Interest selection, calculate the differencespectrum between the average wholesome spectrum and average unwholesomespectrum, and note the maximum difference value that occurs for eachpotential Region of Interest; (v) compare the maximum difference valuesfrom all potential Regions of Interest to select the Region of Interestthat resulted in the greatest maximum difference value as the optimizedRegion of Interest to use for multispectral identification of wholesomeand unwholesome chicken carcasses; (vi) select the wavebandcorresponding to the greatest maximum difference value of the optimizedRegion of Interest as the key wavelength to use for multispectralidentification of wholesome and unwholesome chickens based onreflectance intensity; (vii) using the optimized Region of Interestcalculate the mean and standard deviation of reflectance intensity atthe key wavelength from (vi) for wholesome chickens and calculate themean and standard deviation of reflectance intensity values at the keywavelength for unwholesome chickens; (viii) specify potential pairs ofkey wavebands selected according to local maxima and minima in thedifference spectrum of the optimized Region of Interest; (ix) calculatethe band ratio value for each potential pair of key wavebands for theaverage wholesome Region of Interest reflectance spectrum calculated in(ii) and the average unwholesome Region of Interest reflectance spectrumcalculated in (iii); (x) select the waveband pair corresponding to thegreatest difference between band ratio values for wholesome andunwholesome as the key waveband pair to use for multispectralidentification of wholesome and unwholesome chicken carcasses based onratio value; (xi) using the optimized Region of Interest calculate themean and standard deviation of the two-waveband ratio from (x) forwholesome chickens and calculate the mean and standard deviation of thetwo-waveband ratio for unwholesome chickens; and (xii) construct fuzzylogic membership functions based on the mean and standard deviationvalues for key wavelength (intensity) and two-waveband ratio values forwholesome and unwholesome chickens.
 7. The method of claim 6 wherein aset of hyperspectral images of freshly slaughtered wholesome andunwholesome chicken carcasses is acquired with the use of an imagingsystem with at least one electron-multiplying charge-coupled devicedetector operatively connected to both a spectrograph and a lensassembly.
 8. The method of claim 6 wherein a set of hyperspectral imagesof freshly slaughtered wholesome and unwholesome chicken carcasses isacquired with the use of a lighting system providing continuous waveillumination spanning at least 400 nm to 800 nm in thevisible/near-infrared region of the electromagnetic spectrum of at least10,000 lux (lumen/m²) and a means of providing a dark imagingbackground.
 9. A method of multispectral inspection of freshlyslaughtered chicken carcasses to identify wholesome and unwholesomechicken carcasses on a chicken processing line, comprising: (a)continuous real-time acquisition of line-scan images of freshlyslaughtered chickens on a commercial chicken processing line; b)real-time analysis of individual line-scan images to identify thepresence and entrance of the leading edge of a chicken into the linearfield of view of the imaging inspection system; (c) real-time analysisof individual line-scan images to locate Region of Interest pixels forindividual chickens; (d) real-time calculation of decision output valuesfor Region of Interest pixels in individual line-scan images; (e)real-time analysis of individual line-scan images to identify the exitof the trailing edge of a chicken from the linear field of view of theimaging inspection system; and (f) calculation of average decisionoutput values to identify chickens as being wholesome or unwholesome bycomparison to a threshold value, by use of the following algorithm: (i)acquire a line-scan image and analyze the line-scan image to determineif the starting point coordinate of a chicken has been assigned, if nostarting point coordinate has been assigned then repeat acquisition andanalysis until a line-scan image is encountered for which a startingpoint coordinate has been assigned; (ii) locate the Region of Interestpixels within the line-scan image and calculate the decision outputvalue for each Region of Interest pixel by using the reflectanceintensity and waveband ratio values at the key wavebands as inputs tothe fuzzy logic membership functions for classification, acquire a newline-scan image if no ending point coordinate has been assigned, repeatlocation of the Region of Interest and calculation of decision outputvalues for each Region of Interest pixel for each new line-scan imageuntil a line-scan image is encountered for which an ending pointcoordinate has been assigned; (iii) calculate the average decisionoutput value for the chicken across all Region of Interest pixels usingvalues calculated in (ii); and (iv) compare the average decision outputvalue with the threshold value to identify an individual bird as eitherwholesome or unwholesome.
 10. The method of claim 9 wherein real-timeanalysis of individual line-scan images to identify the presence andentrance of the leading edge of a chicken into the linear field of viewof the imaging inspection system is performed by using the followingalgorithm: (a) examine the 1-dimensional data array whose indicescorrespond to the uppermost 256 pixels of the line-scan image with 1 atthe top of the line-scan image and which contains the relativereflectance values at the 620 nm waveband of the uppermost 256 pixels,if the array contains only values corresponding to background pixelshaving relative reflectance below 0.1 then continue examining subsequentline-scan images until the first non-background pixel or group of pixelsis detected within the array; when any non-background pixels havingrelative reflectance greater than 0.1 are detected, indicating that anew chicken has entered the linear field of view, note the correspondingindex of the first uppermost such pixel and assign this index as the topreference coordinate, if the value of the array at the last index doesnot correspond to a background pixel then note the index of the lastlowermost background pixel in the array and assign this index as thebottom reference coordinate; (b) for the subsequent line-scan image,examine only the array values at the indices corresponding to andincluding the top reference coordinate and the bottom referencecoordinate, within these indices find the index of the first uppermostbackground pixel and the last lowermost background pixel and reassignthese indices to be the top reference coordinate and bottom referencecoordinate respectively; (c) for each subsequent line-scan imagecontinue searching for first and last background pixels between the topreference coordinate and bottom reference coordinate and thenre-assigning the reference coordinates to the corresponding indices; and(d) when a line-scan image is found for which there are no backgroundpixels occurring between the top reference coordinate and the bottomreference coordinate, check whether the top and bottom referencecoordinates are assigned to the same index value, if they are the samethen assign the vertical coordinate of the corresponding image pixel tobe the starting point pixel, if they are not the same then assign themedian of the two indices to be the starting point for the currentchicken being imaged.
 11. The method of claim 9 wherein real-timeanalysis of individual line-scan images to locate Region of Interestpixels for individual chickens is performed by using the followingalgorithm: (a) if the starting point has been assigned for the currentchicken being imaged, examine the line-scan image and find the lowermostnon-background pixel within the line-scan image which may coincide withthe lowermost pixel of the line-scan image if there are no backgroundpixels that the bottom of the line-scan image; (b) find the number ofpixels between and including the starting point coordinate and thelowermost non-background pixel and consider this the reference distance;and (c) with the previously determined values of parameters m and n,each in the range between 0% and 100%, select all pixels within theline-scan image that occur between m % of the reference distance and n %of the reference distance, where the starting point coordinate is at 0%and the lowermost non-background pixel is the at 100%, these selectedpixels comprise the ROI for this line-scan image.
 12. The method ofclaim 9 wherein real-time analysis of individual line-scan images toidentify the exit of the trailing edge of a chicken from the linearfield of view of the imaging inspection system is performed by using thefollowing algorithm: (a) if the starting point has been assigned for thecurrent chicken being imaged, examine the relative reflectance value at620 nm of the line-scan image at the starting point coordinate; (b) ifthe value corresponds to a non-background pixel, relative reflectancegreater than 1.0, do not assign a value to be the ending pointcoordinate; and (c) if the value corresponds to a background pixel,relative reflectance less than 0.1, then assign the starting pointcoordinate to be the ending point coordinate, indicating that theprevious line-scan image was the last line-scan to be analyzed for thecurrent chicken being imaged and no additional line-scans are to beanalyzed.
 13. The method of claim 9 wherein real-time calculation ofdecision output values for each Region of Interest pixel in theline-scan images is performed using a fuzzy logic classifier defined bythe following equation:D_(o)=max[min{w₁,w₂},min{u₁,u₂}] wherein w₁ and u₁ are fuzzy membershipvalues for the pixel based on the reflectance intensity at the keywavelength, w₂ and u₂ are fuzzy membership values based on thetwo-waveband ratio, min indicates a minima operation that selects thesmaller of the two values, max indicates a maxima operation that selectsthe larger of the two values, and D_(o) is the decision output value forthe pixel.
 14. A process for automated online inspection of freshlyslaughtered chicken carcasses on a processing line to identify wholesomeand unwholesome chickens, comprising: (a) illuminating said chickencarcasses with a source of electromagnetic radiation having apredetermined spectral content, (b) detecting radiation from said sourcereflected by said chicken carcasses in each of two key wavelengths, λ₁and λ₂, using an imaging system that correlates radiation intensity ateach of the two key wavelengths with spatial pixels of the images ofsaid chicken carcasses, (c) identifying the entrance and exit of each ofsaid chicken carcasses through the field of view of the imaging system,(d) identifying selected areas of each image of said chicken carcassesfor which the values of reflected radiation intensity will be used incalculations to identify wholesomeness or unwholesomeness, (e)calculating the ratio of the radiation intensity at λ₁ divided by theradiation intensity at λ₂ for each pixel in the selected areas of eachimage, (f) calculating decision output values for each image pixel usinga fuzzy logic classifier, and (g) generating an identification of beingwholesome or unwholesome for each of said chicken carcasses based on thecomparison of the average decision output for the selected area of eachchicken image with a decision-making threshold value.
 15. The process ofclaim 14 wherein λ₁ is from about 570 nm to about 590 nm and λ₂ is fromabout 610 nm to about 630 nm.
 16. The process of claim 14 wherein λ₁ isabout 580 nm and λ₂ is about 620 nm.
 17. The process of claim 14 whereinλ₁ is 580 nm and λ₂ is 620 nm.
 18. A process for automated onlineinspection of freshly slaughtered chicken carcasses on a processing lineto identify wholesome and unwholesome chickens, comprising following theprocedure in FIG.
 4. 19. The imaging system of claim 1 wherein saidsystem further comprises a means of creating a dark imaging background.